/*
 * Copyright 1999-2017 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package studio.raptor.sqlparser.ast;

import java.util.ArrayList;
import java.util.List;
import studio.raptor.sqlparser.ast.statement.SQLSelectOrderByItem;
import studio.raptor.sqlparser.visitor.SQLASTVisitor;

public class SQLOrderBy extends SQLObjectImpl {

  protected final List<SQLSelectOrderByItem> items = new ArrayList<SQLSelectOrderByItem>();

  // for postgres
  private boolean sibings;

  public SQLOrderBy() {

  }

  public SQLOrderBy(SQLExpr expr) {
    SQLSelectOrderByItem item = new SQLSelectOrderByItem(expr);
    addItem(item);
  }

  public void addItem(SQLSelectOrderByItem item) {
    if (item != null) {
      item.setParent(this);
    }
    this.items.add(item);
  }

  public List<SQLSelectOrderByItem> getItems() {
    return this.items;
  }

  public boolean isSibings() {
    return this.sibings;
  }

  public void setSibings(boolean sibings) {
    this.sibings = sibings;
  }

  protected void accept0(SQLASTVisitor visitor) {
    if (visitor.visit(this)) {
      acceptChild(visitor, this.items);
    }

    visitor.endVisit(this);
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((items == null) ? 0 : items.hashCode());
    result = prime * result + (sibings ? 1231 : 1237);
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (getClass() != obj.getClass()) {
      return false;
    }
    SQLOrderBy other = (SQLOrderBy) obj;
    if (items == null) {
      if (other.items != null) {
        return false;
      }
    } else if (!items.equals(other.items)) {
      return false;
    }
    if (sibings != other.sibings) {
      return false;
    }
    return true;
  }

  public void addItem(SQLExpr expr, SQLOrderingSpecification type) {
    SQLSelectOrderByItem item = createItem();
    item.setExpr(expr);
    item.setType(type);
    addItem(item);
  }

  protected SQLSelectOrderByItem createItem() {
    return new SQLSelectOrderByItem();
  }
}
